function remSize() {
  let deviceSize = document.documentElement.clientWidth || window.innerWidth;
  if (deviceSize > 750) {
    deviceSize = 750;
  }
  if (deviceSize < 320) {
    deviceSize = 320;
  }
  document.documentElement.style.fontSize = deviceSize / 7.5 + "px";

  document.querySelector("body").style.fontSize = 0.3 + "rem";
}
remSize();
window.onresize = function () {
  remSize();
};
